Conductors of Electricity

Most materials fall into two groups: conductors and insulators.
A conductor allows electrons to flow through it.
An insulator is a barrier to electricity.
An insulator may act as a store of electricity known as static electricity.
There is a small third group called semi conductors - these are used in electronics.
The current is carried by ELECTRONS.
Metals contain a "sea" of free electrons (negatively charged) which flow through the metal.
This is what allows electric current to flow so well in all metals.
Electric current will only flow if there are charges which can move freely (electrons).
There are some things that you need to know for the exam about the difference between CONVENTIONAL and ELECTRICAL current.
CONVENTIONAL current flows from POSITIVE TO NEGATIVE.
ELECTRICAL current flows from NEGATIVE TO POSITIVE.
So electrons flow opposite to the flow of conventional current.